Domestic incinerator



Dec. 12, 1967 F. s. MALICIK 3,35 ,3 5

DOMESTIC INCINERATOR Filed Oct. 22, 1965 POWER SUPPLY INVENTOR Franklin8. Molick ATTORNEY United States Patent M 3,357,373 DOMESTIC INCINERATORFranklin S. Malick, Monroeville, Pa., assignor to Westinghouse ElectricCorporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Oct.22, 1965, Ser. No. 501,362 3 Claims. (Cl. 110-8) ABSTRAGT OF THEDISCLOSURE A domestic incinerator in which waste material is compactedinto an imporous plug exposed at its bottom to the top of a combustionchamber for controlled burning of such bottom at a rate which isautomatically controlled according to combustion chamber temperature byswitching admission of combustion air into the combustion chamber atdifferent burning-rate-inducing inlet locations while also providing forelectrical heating of such air admitted at the inlet location having thehigher burning rate inducement.

An object of the invention is to provide means to control the rate ofcombustion in a device where the waste material is compacted into animporous mass and a thin layer of one face of such mass is maintained ina state of combustion.

It has been discovered that substantially fifteen hundred degreesFahrenheit is necessary to reduce trash to a clear and odorless gas. Ithas further been discovered that higher temperatures render the disposalof trash more eflicient and speed the operation. However, there is alimit, for such higher temperatures shorten the life of the combustionchamber and other parts of the apparatus. Moreover the highertemperatures result in the formation of slag which, if present insufficient quantities, tends to clog the combustion chamber, whereassomewhat lower temperatures produce brittle matter which can be easilycleaned out. It is therefore important that a suitable temperature beset and closely maintained, a temperature that will produce as high aspeed of operation as possible without reaching the point wheredestruction and clogging of the apparatus takes place.

In accordance with the present invention electrical means are employedto induce combustion and a supply of air for maintaining combustion isfed into the combustion chamber. It has been found that combustion ofthe burning face of the plug of compacted material will take place witha higher intensity when the air for combustion is brought in closer tothe burning face than when it is brought in at a distance therefrom.

It is to be noted that at the temperature at which the combustionchamber is operated heat is transmitted inside the chamber by radiationso that the chamber and the burning face of the plug are all at aboutthe same tem perature. The higher the velocity of the combustion airover this hot face of the plug the higher the rate of combustion ofcarbon at the face. Since the quantity of combustion air remainsapproximately the same and since the conduction losses through thechamber wall remain the same, the temperature will rise when thecombustion rate increases.

Accordingly, a temperature probe is employed to sense the temperature ofthe combustion chamber. When the temperature falls below thepredetermined point, this device will control an air valve to direct theincoming air for combustion nearer the burning face of the plug, therebyincreasing the air velocity and the combustion rate and thereforecausing the temperature to rise to a predetermined level. Alternatively,when the temperature rises above this predetermined level, the air valvewill be operated to direct the air for combustion further away from theburning face.

A feature of the invention is the combination of a temperature probeoperating an electrical contact, a solenoid operated air valve andalternative air ducts controlled thereby, one for delivering air forcombustion near the burning face of the plug and the other fordelivering such air at a distance therefrom.

Another feature of the invention resides in the provision of means topreheat the air supply when it is to be delivered substantially at theface of the plug, and to omit such preheating means when the air supplyis to be delivered at a distance therefrom. It will be understood thatthe electrical means used to induce combustion is not necessarily incontinuous operation, even though the combustion air is flowing incontact therewith, and that the combustion of the face of the plug ofcompacted material is sufficient without preheat for longer or shorterperiods to maintain combustion. The electrical heaters are usedprimarily during start ups and periods when wet materials are beingburned. The heaters are controlled by a separate probe, and cutoff ofelectric heat occurs at a temperature about F. lower than thetemperature at which air switching occurs.

Another feature of the invention is the provision of an air preheatingchamber constructed in the line of the first duct used for deliveringthe combustion air substantially to the face of the burning plug. By theuse of such a chamber the air delivered to the face of the imporous plugmay be sufiiciently high in temperature to induce combustion thereof andduring operation sufiiciently high in temperature to supply theadditional heat required to maintain the chamber temperature whenburning a wet load. Generally, the walls of the combustion chamber areconstructed of ceramic material and this air preheating chamber isfashioned within the mass of such ceramic material and is thus heatinsulated from the outer surfaces of the device both for safety andefficiency.

Other features of the present device are disclosed in applications Ser.No. 329,044, filed Dec. 9, 1963 by Franklin S. Malick, now Patent No.3,313,253, and Ser. No. 347,886, filed Feb. 27, 1964 by Bernard Miller,which are herein considered prior art disclosures and which areintroduced herein and made a part hereof.

Another application Ser. No. 501,546, filed on even date herewith in thename of Summer F. Wiley, Jr. discloses a means of the same nature asthat herein disclosed, but adjusted to operate was to establish andmaintain a specific temperature suitable for the destruction of tincans.

Other features will appear hereinafter.

The drawings consist of a single sheet having a single figure in theform of a schematic representation of an incinerator partly in crosssection showing the various components of the device and the relation ofsuch components one to the other.

The device consists substantially of a metal trash bin 1, having an airtight lid 2, provided with a conventional compressed air inlet 3. Atrash-compacting means in form of a bag 4 is arranged to be inflated bythe compressed air from the inlet 3 so that trash 5 may be compressedinto an imporous mass and forced downwardly until its lower face lodgesat a given level herein, by way of example, fixed by a set of grate bars6. This lower face then substantially becomes one wall of a combustionchamber 7 so that this lower face may be said to be maintained at thejunction of the combustion chamber and the trash bin. The combustionchamber is surrounded by heat insulation 8 which may be ceramicmaterial.

A chamber 9, also covered by this ceramic material, houses an electricalresistance heater 10, so that air from 3 the supply pipe 11, switchedby'the selector valve 12 into a first duct 13, may be heated and't'henpassed through a manifold 14 and air distribution means 15 in the formof pipes provided with a plurality of orifices to project jets upwardlytoward the face of the plug of cornpacted material. By this meanscombustion of the face may be induced and maintained.

A conventional temperature probe 16 protrudes into the combustionchamber 7 and controls a conventional electrical switch 17 which in turncontrols a solenoid valve actuator 18. By this means, when thetemperature in the combustion exceeds a predetermined point, the valve12 may be operated to divert the air supply in the inlet 11 into asecond duct 19, supplying a region of the combustion chamber 7 remotefrom the burning plug surface via an outer annular chamber 20 and radialports 21, so that now the air for maintaining combustion is introducedat a distance from the face of the plug of oxidizable material 5. Asecond probe (not shown) controlling a second switch (not shown) can beemployed for turning on and off the heaters 10, or the probe 16 andswitch 17 may serve such function, as shown in the drawing.

The air supply for combustion may be supplied under pressure through thepipe 11 or the same effect may be produced by suction means provided inthe exhaust 22 exiting from annular chamber 20, or both such means maybe provided.

Various practical embodiments of this scheme may be provided, but allsuch embodiments will contain one or more probes to sense thetemperature in the combustion chamber, which .will operate either tosupply air for combustion substantially at the face of the plug, or,alternatively, to supply combustion air to another point in thecombustion chamber at a distance from such face, and to preheat the airsupplied adjacent the face of the plug, when necessary to maintainsuitable combustion.

The trash bin is air tight so that combustion of only a thin layer ofthe face of the plug of compacted imporous material takes place and,through the switching back and forth of the air valve 12 under controlof the probe 16 on either side of the predetermined fixed temperaturevalue, this value is substantially maintained.

What is claimed is:

1'. In an incinerator device having ac'o'mbustio'n chamber (7)surmounted by a trash bin (1), and means (4, 6) in the trash bin forcompacting trash (5) therein into an imporous plug of oxidizable.material with its bottom face constituting an upper wall of thecombustion chamher:

(a) an air supply pipe (11),

(b) first air conveying means (13, 9, 14,15) for delivering air into thetop of the combustion chamber (7) onto the bottom face of the plug oftrash (5) to increase rate of burning thereof,

(c) second air conveying means (19, 20, 21) for delivering air into thebottom of the combustion chamher (7 to decrease rate of burning of thebottom of the plug of trash (5), and

(d) air switching means (12, 18, 17, 16) including a selector valve (12)and temperature-responsive actuator means (16, 17, 18) thereforoperative to open one or the other of the first and second air conveyingmeans to the air supply pipe (11) according to temperature changes inthe combustion chamber (7 2. The incinerator device of claim 1, furthercomprising:

(e) air heating means (10, 17, 16) including an electrical resistanceheater (10) and temperature-responsive control means (16, 17) thereforoperative to heat the air passing through said first air conveying means(13, 9, 14, 15) according to the temperature in the combustion chamber(7).

3. The incinerator device of claim 2, wherein the temperature-responsiveactuator means (16, 17, .18) comprises a solenoid (18) for operating theselector valve (12), and the temperature-responsive control means, (16,17) for the resistance heater (10) as a means for controlling suchsolenoid.

References Cited UNITED STATES PATENTS JAMES W. WESTHAVER, PrimaryExaminer.

1. IN AN INCINERATOR DEVICE HAVING A COMBUSTION CHAMBER (7) SURMOUNTEDBY A TRASH BIN (1), AND MEANS (4,6) IN THE TRASH BIN FOR COMPACTINGTRASH (5) THEREIN INTO AN IMPOROUS PLUG OF OXIDIZABLE MATERIAL WITH ITSBOTTOM FACE CONSTITUTING AN UPPER WALL OF THE COMBUSTION CHAMBER: (A) ANAIR SUPPLY PIPE (11), (B) FIRST AIR CONVEYING MEANS (13, 9, 14, 15) FORDELIVERING AIR INTO THE TOP OF THE COMBUSTION CHAMBER (7) ONTO THEBOTTOM FACE OF THE PLUG OF TRASH (5) TO INCREASE RATE OF BURNINGTHEREOF, (C) SECOND AIR CONVEYING MEANS (19, 20, 21) FOR DELIVERING AIRINTO THE BOTTOM OF THE COMBUSTION CHAMBER (7) TO DECREASE RATE OFBURNING OF THE BOTTOM OF THE PLUG OF TRASH (5), AND (D) AIR SWITCHINGMEANS (12, 18, 17, 16) UNCLUDING A SELECTOR VALVE (12) ANDTEMPERATURE-RESPONSIVE ACTUATOR MEANS (16, 17, 18) THEREFOR OPERATIVE TOOPEN ONE OR THE OTHER OF THE FIRST AND SECOND AIR CONVEYING MEANS TO THEAIR SUPPLY PIPE (11) ACCORDING TO TEMPERATURE CHANGES IN THE COMBUSTIONCHAMBER (7).